Our objective is to conduct a detailed morphological study on the inner ears of animals and postmortem humans with both transmission and scanning electron microscopes. Special emphasis will be placed on study of the spiral ganglion cells and the nerve fibers in the osseous spiral lamina and their distribution in the organ of Corti in normal and pathological ears. We will also conduct an extensive study on endolymphatic hydrops in animals in an effort to further define morphological changes, to study the effect of obliteration of the ductus reuniens, and to control hydrops by drug application. These studies will provide basic information for the understanding and treatment of deafness and Meniere's disease.